@article{isik_gumpertz_li_goldfarb_sun_2008, title={Analysis of cellulose microfibril angle using a linear mixed model in Pinus taeda clones}, volume={38}, ISSN={["1208-6037"]}, DOI={10.1139/X08-010}, abstractNote={ Variation in microfibril angle (MFA) (degrees) among loblolly pine ( Pinus taeda L.) full-sib families and clones was investigated using 43 clones from nine full-sib crosses tested at two locations. When the experiments were 12 years old, a total of 316 trees were drilled and 12 mm thick wood increment cores were collected. MFA for each growth ring in the wood core was measured using the SilviScan-2 tool. A quadratic mixed model was fitted to evaluate the MFA variation over different rings. Among the error covariance structures tested in the model, autoregressive order 1 was the best model for producing MFA estimates with the smallest errors. Estimated MFA was about 33° in the pith (ring 1) of the trees and decreased to 18° in the outer wood (ring 11). Full-sib crosses and clones within crosses explained about 12.5% of the total phenotypic variation. Repeatability of full-sib family means (H2f = 0.46) was moderate but repeatability of clone means was high (H2c = 0.79). Although it is possible to improve (decrease) MFA with recurrent selection in tree improvement programs to improve lumber quality, cost efficient and rapid methods for measuring MFA are needed. }, number={6}, journal={CANADIAN JOURNAL OF FOREST RESEARCH}, publisher={Canadian Science Publishing}, author={Isik, Fikret and Gumpertz, Marcia and Li, Bailian and Goldfarb, Barry and Sun, Xuan}, year={2008}, month={Jun}, pages={1676–1689} }
 @article{peng_sun_spagnola_hyde_spontak_parsons_2007, title={Atomic layer deposition on electrospun polymer fibers as a direct route to Al2O3 microtubes with precise wall thickness control}, volume={7}, ISSN={["1530-6984"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000244867400032&KeyUID=WOS:000244867400032}, DOI={10.1021/nl062948i}, abstractNote={Atomic layer deposition (ALD) of Al2O3 on electrospun poly(vinyl alcohol) microfiber templates is demonstrated as an effective and robust strategy by which to fabricate long and uniform metal-oxide microtubes. The wall thickness is shown to be precisely controlled within a molecular layer or so by adjusting the number of ALD cycles utilized. By judicious selection of the electrospinning and ALD parameters, designer tubes of various sizes and inorganic materials can be synthesized.}, number={3}, journal={NANO LETTERS}, author={Peng, Qing and Sun, Xiao-Yu and Spagnola, Joseph C. and Hyde, G. Kevin and Spontak, Richard J. and Parsons, Gregory N.}, year={2007}, month={Mar}, pages={719–722} }
 @article{sun_shankar_boerner_ghosh_spontak_2007, title={Field-driven biofunctionalization of polymer fiber surfaces during electrospinning}, volume={19}, ISSN={["1521-4095"]}, DOI={10.1002/adma.200601345}, abstractNote={Surface-biofunctionalized synthetic polymer fibers composed of a fiber-forming host polymer and an oligopeptide conjugate are prepared by electrospinning. The conjugate consists of a polypeptide segment and a polymer block that is compatible with the host polymer. Because the more polarizable peptide segment migrates to the surface during electrospinning, peptide surface enrichment (see figure and inside cover) is achieved in a single step without further treatment.}, number={1}, journal={ADVANCED MATERIALS}, author={Sun, Xiao-Yu and Shankar, Ravi and Boerner, Hans G. and Ghosh, Tushar K. and Spontak, Richard J.}, year={2007}, month={Jan}, pages={87-+} }
 @article{chin_sun_roberts_spivey_2006, title={Preferential oxidation of carbon monoxide with iron-promoted platinum catalysts supported on metal foams}, volume={302}, ISSN={["1873-3875"]}, DOI={10.1016/j.apcata.2005.11.030}, abstractNote={A series of 5 wt% Pt/0.5 wt% Fe/γ-Al2O3 catalysts supported on metal foams of different geometries were synthesized and tested for preferential oxidation of a low CO concentration in the presence of a high H2 concentration. The catalysts were tested in a fixed bed adiabatic reactor at a total pressure of 0.2 MPa (absolute) to simulate fuel processor operating pressure. The inlet temperature was varied from 80 °C to 170 °C, and the gas hourly space velocity ranged from 5000 h−1 to 45,000 h−1. The inlet gas composition to the reactor reproduced that of the effluent stream from the water-gas-shift reactor in a typical fuel processor: H2 42%, CO2 9%, H2O 12%, CO 1.0%, O2 0.5–1.0%, and N2 35–35.5%. The geometry of a foam is characterized by the volume fraction of solid material (cell density) and by the number of pores per inch. The catalysts with lower cell densities generally exhibited higher CO conversions and selectivities. Under most operating conditions, the CO conversion and selectivity of the best metal foam catalysts were comparable to those of a 400 cells per square inch, ceramic straight-channel monolith with the same nominal catalyst loading. Both the reverse water-gas-shift (r-WGS) reaction and transport resistances affected the performance of these catalysts. Under adiabatic conditions, the r-WGS reaction made it impossible to achieve low outlet CO concentrations. The effects of space velocity and linear velocity were studied independently using various catalyst lengths and volumetric gas flow rates. At a constant space velocity, the CO conversion increased with higher linear velocities, suggesting a significant mass transfer resistance between the bulk gas and the catalyst surface.}, number={1}, journal={APPLIED CATALYSIS A-GENERAL}, author={Chin, P and Sun, XL and Roberts, GW and Spivey, JJ}, year={2006}, month={Mar}, pages={22–31} }
 @article{roberts_chin_sun_spivey_2003, title={Preferential oxidation of carbon monoxide with Pt/Fe monolithic catalysts: interactions between external transport and the reverse water-gas-shift reaction}, volume={46}, ISSN={["1873-3883"]}, DOI={10.1016/j.apcatb.2003.07.002}, abstractNote={A series of Pt/Al2O3 catalysts, promoted with Fe and supported on 400 cpsi (cells per square inch) (62 cells/cm2) ceramic straight-channel monoliths, was synthesized and evaluated for preferential oxidation (PROX) of a low concentration of CO in the presence of a high concentration of H2. These catalysts were evaluated in an adiabatic reactor at a total pressure of 0.20 mPa inlet temperatures of 80–170 °C, and a space velocity of 30,000 h−1. The inlet gas composition was—H2: 42%, CO2: 9%, H2O: 12%, CO: 0–1.0%, O2: 0–1.0%, with N2 as the balance. For a catalyst containing 5 wt.% Pt in the washcoat, the carbon monoxide and oxygen conversions increased as the iron concentration in the washcoat was increased up to about 0.5 wt.% Fe. The reverse water-gas-shift (r-WGS) reaction played an important role in determining the outlet CO concentration. A catalyst with 1.6 g/in.3 (0.098 g/cm3) of an alumina washcoat containing 5 wt.% Pt/Al2O3 promoted with 0.5 wt.% Fe was selected for detailed investigation. The effects of both space velocity and linear velocity were studied. External transport was a significant resistance with this catalyst, at the above experimental conditions. The external resistances to heat and mass transfer, coupled with the effect of the r-WGS reaction, reduced the observed CO conversion and selectivity.}, number={3}, journal={APPLIED CATALYSIS B-ENVIRONMENTAL}, author={Roberts, GW and Chin, P and Sun, XL and Spivey, JJ}, year={2003}, month={Nov}, pages={601–611} }
 @article{sun_roberts_2003, title={Synthesis of higher alcohols in a slurry reactor with cesium-promoted zinc chromite catalyst in decahydronaphthalene}, volume={247}, ISSN={["0926-860X"]}, DOI={10.1016/S0926-860X(03)00093-0}, abstractNote={The synthesis of higher alcohols from H2/CO mixtures was studied in a continuous slurry reactor using unpromoted “zinc chromite” catalyst and the same catalyst promoted with 6 wt.% cesium (Cs). Decahydronaphthalene (DHN) was used as the slurry liquid. Two temperatures 375 and 400 °C, and three H2/CO feed ratios 0.5, 1.0, and 2.0 (mol/mol), were explored. The pressure, 13.6 MPa (2000 psig), and the gas hourly space velocity (GHSV), 5000 standard l/(kg (cat) h), were constant. Compared with unpromoted zinc chromite, the Cs-promoted catalyst shifted the product distribution away from methanol towards higher alcohols, although methanol was still the major product. The higher alcohols were primarily ethanol, 1-propanol and isobutanol. Higher temperature favored higher alcohol synthesis (HAS), and a higher H2/CO ratio led to lower oxygenate selectivity and higher hydrocarbon selectivity. These trends were more pronounced with the Cs-promoted catalyst than with the unpromoted catalyst. The performance of both catalysts was comparable to that of similar catalysts in fixed-bed reactors operating at approximately the same conditions.}, number={1}, journal={APPLIED CATALYSIS A-GENERAL}, author={Sun, XL and Roberts, GW}, year={2003}, month={Jul}, pages={133–142} }
 @article{sun_jones_gesick_xu_roberts_2002, title={Liquid/catalyst interactions in slurry reactors: changes in tetrahydroquinoline composition during methanol synthesis over zinc chromite}, volume={231}, ISSN={["1873-3875"]}, DOI={10.1016/S0926-860X(02)00069-8}, abstractNote={The excellent thermal stability of tetrahydroquinoline (THQ) under reducing conditions [1] has led to its use as a slurry liquid for several catalytic reactions: the synthesis of methanol over “zinc chromite” catalyst [2], the synthesis of higher alcohols over promoted “zinc chromite” [3], and the dehydrogenation of methanol to formaldehyde over various copper-containing catalysts [4], [5]. However, the rate and selectivity of alcohol synthesis over zinc chromite catalyst was much different with THQ as the slurry liquid than with several similar compounds. It also was found that THQ was alkylated during both alcohol synthesis and methanol dehydrogenation. To understand the behavior of THQ-derived slurry liquids, various analyses were carried out on a sample of this liquid that was obtained after 240 h of continuous operation under methanol synthesis conditions. Silica gel liquid chromatography (LC) and high performance LC (HPLC) were used to fractionate the “spent” slurry liquid, while gas chromatography/mass spectroscopy (GC/MS), Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy were applied to identify the major compounds. Methyl-, dimethyl-, and trimethyl-THQ comprised more than 80% of the “spent” slurry liquid. The balance primarily was various methylated indoles. A methyl group always was attached to the N atom in the ring structure. There was no evidence of further alkylation of methyl groups. These results appear to eliminate the possibility that the observed differences between THQ and similar hydrocarbon slurry liquids result from the nucleophilicity of secondary amines in the liquid. They also suggest that alkylation of THQ will eventually stop as the ring positions in THQ become saturated. A mechanism for the alkylation of THQ is proposed.}, number={1-2}, journal={APPLIED CATALYSIS A-GENERAL}, author={Sun, XL and Jones, NW and Gesick, JC and Xu, LL and Roberts, GW}, year={2002}, month={May}, pages={269–280} }